<!DOCTYPE html>
<html>
<head>
	<title></title>
	<style type="text/css">
		
	</style>
	<script type="text/javascript">
		var n1 = 5;
		var n2 = 6;
		var tmp;
		tmp = n1;
		n1 = n2;
		n2 = tmp;
		console.log(n1, n2);
	</script>
	<script type="text/javascript" src="demo17_index.js"></script>
</head>
<body>
	<!-- 行内js -->
	<input type="button" onclick="alert('Hello world')" value="按钮" \>
</body>
</html>